package com.bjpowernode.javase.collection.concurrentHashMap;

import java.util.HashMap;
import java.util.concurrent.ConcurrentHashMap;

public class Test0 {
    public static void main(String[] args) {
        ConcurrentHashMap<String,Object> concurrentHashMap = new ConcurrentHashMap<>();
        Object put = concurrentHashMap.put("a", "A");
        System.out.println(put);

        Object put1 = concurrentHashMap.put("a", "B");
        System.out.println(put1);

        HashMap map = new HashMap();
        Object put2 = map.put("sun", "usn");
        System.out.println(put2);
        Object put3 = map.put("sun", "u");
        System.out.println(put3);
    }
}
